Braking Improvement ?

I have just bought a new 2004 Giant Yukon (with standard cheapy v-brakes) and despite the fact that I understand it is only an entry-level bike, I am very pleased with it apart from the brakes !. I only ride country parks and light trails / woods and weigh 15 stone so I understand it takes some stopping, but the performance of the brakes is terrible. Is there any way I can improve them ?, can I buy better pads / calipers / cables / levers ..etc ?. Any advice would be most appreciated.

In your case what will help you out the most is to swap brake pads for a more grippy compound. Another thing that would help is to install a brake arch so the mounting posts of the Vees do not bend when you're braking.

I don't know the brakes on the Yukon, but verify it doesn't have the infamous "Shimano Brake Modulators". Those are a kind of springs that mount on the braking line (cable) and are supposed to reduce the bite on Vee's so people wouldn't lock the wheels so easily.

This idea and the short arm on the first mechanical disk brakes from Shimano are one of the Shimano's Big F***-Up's. They thought we can not modulate a brake when we kept wanting for more power.